Load packaging methods and apparatuses of this type have hitherto been known as disclosed in JP S59-46845 B and JP H08-508223 A.
In what are shown and described in the former of the above prior art references, a load material is placed on a conveyer whose upper and lower surfaces are driven to move in an identical direction and at an identical speed, and the load material carried on the moving conveyer is wrapped, together with the conveyer, with a stretch film of stretchable material. When the load material in this state is moved to a position beyond the downstream end of the conveyer where it comes off the conveyer, the stretch film is allowed to shrink, leaving only the load material wrapped therewith.
Also, the latter of the above prior art references describes its first form of implementation in which a load material placed on a first table is wrapped with a stretch film in a direction perpendicular to a horizontal direction. After this load material is moved onto a second table, the second table is turned horizontally about a vertical axis of rotation to further wrap the load material on the second table with a stretch film in a direction perpendicular to the direction in which the load material was wrapped on the first table with the stretch film.
The latter of the above prior art references also describes its second form of implementation in which a wrapping means is rotated in a horizontal plane and a load material is rotated about a horizontal axis of rotation, namely in a vertical plane so that rotating the wrapping means while the load material is being rotated causes the load material to be wrapped both vertically and horizontally.
Both of these prior art references require, however, that a load material to be wrapped with a stretch film or films be pre-consolidated (e. g., into a carton shape or the like rectangular parallel piped), and thus are totally unsuitable to package a bulk material such as a mass of wet feeding stuff or a mass of refuse or waste without a hitch.
A first object of the present invention is, therefore, to provide a load packaging method and apparatus whereby a bulk material to be packed such as a mass of wet feeding stuff or a mass of refuse or waste can be compressed or consolidated into a rectangular parallelepiped so that it can readily be wrapped with stretch film.
Also, what is shown and described in the former of the above prior art references allows a stretch film to be wrapped around a load material only about its horizontal axis and hence is unsuitable to package a cubic load.
On the other hand, what is shown and described in the latter of the above prior art references allows a stretch film to be wrapped around a load material about both its horizontal and vertical axes. In its first form of implementation, however, wrapping a load material in turn on two tables, first on a first table and then on a second table, with stretch films in two directions different from each other requires a roll of film to be tilted by 90 degrees, and requires the second table to be rotated before completing the wrapping operation. The inconveniences have therefore been encountered there, too. In particular, not only is the double wrapping operation cumbersome, but also the apparatus for performing this operation becomes complicated in mechanism.
Also, while this second form of implementation allows a load material staying at a given position to be doubly wrapped with stretch films about both its vertical and horizontal axes, this technique, too, has been found inconvenient in that it necessitates a complicated and large-scaled apparatus makeup because of the need for separate mechanisms for wrapping stretch film around the load material about both its vertical and horizontal axes, respectively.
A second object of the present invention is, therefore, to provide a load packaging method and apparatus whereby a pressed load material for packaging can simply be wrapped over its entire peripheral surfaces with stretch film only by wrapping the load material only about its one axis with either stretch film alone or both stretch and subsidiary films whereby a highly water-tight package is obtained without water soaking into or out of its inside.